IdNr vs. Steuernummer: two different numbers
Most people arriving in Germany encounter both terms and assume they are the same. They are not.
The Steuerliche Identifikationsnummer (IdNr or Steuer-ID) is an 11-digit permanent number assigned to you personally by the Federal Central Tax Office (Bundeszentralamt für Steuern, BZSt). It does not change if you move, change your name, or switch employers. You keep it for life.
The Steuernummer is a different number assigned by your local Finanzamt and is used for filing tax returns. It can change if you move to a different tax district. Employers sometimes ask for both — but your payroll always runs on the IdNr.
When someone says "your tax ID" in an employment or banking context, they almost always mean the IdNr. This guide covers the IdNr.
How you receive it
Your Steuer-ID arrives automatically after your Anmeldung (address registration at the Bürgeramt). The BZSt processes the registration data and sends a letter to your registered address. There is no online portal, no email, no app — it comes only by physical post.
Typical delivery time: 2 to 4 weeks after Anmeldung, though it can take up to 6 weeks during high-volume periods. The letter is a plain white envelope from the BZSt — do not throw it away assuming it is junk mail.
Critical rule: check your mailbox regularly in the weeks after Anmeldung. The letter is not trackable and will not be re-sent automatically if it gets lost. Keep the letter once it arrives.
What to do if it does not arrive
If 6 weeks have passed after Anmeldung and no letter has arrived, request the number directly from the BZSt:
Online request: Go to the BZSt website and use the form under "Steuerliche Identifikationsnummer" → "Anforderung der IdNr". You will need your name, date of birth, and current registered address. The BZSt then sends the number by post again — allow another 2 to 3 weeks.
Postal request: Write a letter to the BZSt (Bundeszentralamt für Steuern, 53221 Bonn) with your full name, date of birth, registered address, and a request for your IdNr. Include a copy of your Anmeldebestätigung (registration confirmation) to speed processing.
Payroll gap: If your employer needs the number for payroll before it arrives, ask HR whether they can process you under a provisional tax class (Lohnsteuerklasse) while you wait. Most payroll systems allow a 3-month provisional window before the IdNr becomes mandatory for accurate withholding.
Where you actually use it
The IdNr is required in a specific set of contexts. Know these before you need them:
- Employer payroll setup — your employer enters your IdNr into their payroll system to retrieve your correct tax class and deductions electronically from the Finanzamt
- ELSTER registration — required to create your account on the official tax portal
- Health insurance enrollment — statutory health insurers (GKV) register members with the IdNr for contribution tracking
- Tax return filing — must appear correctly on your Lohnsteuerbescheinigung (annual wage tax statement)
- Kindergeld applications — the Familienkasse requires the IdNr of each parent and child
- Some bank account openings — not universally required, but some banks ask for it during the account setup for tax reporting purposes
What you do NOT need it for
- Anmeldung itself — the registration happens first; the IdNr comes after
- Day-to-day transactions — no shop, restaurant, or service needs your IdNr
- Standard identity verification — your Personalausweis or passport handles this
- Most rental applications — landlords may ask for income proof but not the IdNr itself
Security: who legitimately asks for it
The IdNr is a sensitive identifier. Once someone has it combined with your name and date of birth, they can potentially misuse it in tax fraud.
Legitimate requestors: your employer (once, during payroll setup), your GKV insurer (once, during enrollment), the Familienkasse (for child benefit), your Finanzamt, ELSTER, and your German bank (sometimes).
Who should NOT receive it: job applications, online forms you did not initiate, unsolicited emails claiming to be from the Finanzamt or BZSt, real estate platforms.
If you receive an email asking you to "verify your Steuer-ID" or submit it via a link — this is phishing. The BZSt and Finanzamt communicate by post, not email.
If you leave Germany
The IdNr remains valid even after you deregister from Germany (Abmeldung). You may need it to:
- File a final German tax return for the year you left
- Claim tax refunds from German employers after departure
- Handle any outstanding Finanzamt correspondence
The number is not deactivated. Store it in a secure place alongside your Anmelde- and Abmeldebestätigungen.
Quick reference
| Item | Detail |
|---|---|
| Length | 11 digits |
| Who issues it | BZSt (Bundeszentralamt für Steuern) |
| When it arrives | 2–6 weeks after Anmeldung, by post |
| Does it change? | Never — permanent for life |
| Cost | Free |
| What to do if lost | Request via BZSt website or post |